J3, J03, J 3 or J-3 may refer to:
Roads
editSubmarines
edit- Junsen type submarine
- HMAS J3, an Australian submarine
Aircraft
edit- Junkers J 3, a German Junkers aircraft
- J-3, a U.S. Navy airship
- Piper J-3, a 1938 light aircraft
Other uses
edit- J3 perturbation, gravitational force caused by an imperfect symmetry north–south of an object being orbited
- J3 Operations Directorate, part of the US Joint Chiefs of Staff
- GS&WR Class J3, an Irish steam locomotive
- JAC J3, a subcompact car produced by JAC Motors
- Janko group J3, in mathematics
- Eupheme (temporarily designated S/2003 J 3), a satellite of Jupiter
- J3 League, Japanese football league
- Northwestern Air IATA code
- J03: acute tonsillitis ICD-10 code
- Triangular cupola, Johnson Solid number 3
- Samsung Galaxy J3, a smartphone by Samsung
- J3 battlecruiser, a British military vessel design from 1920s* LNER Class J3, a class of British steam locomotives